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Rolson shake torch

duke37

Jan 9, 2011
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I was asked to look at a Rolson torch which should be shaken to generate energy to light a LED.
I wonder if it ever worked as a shake torch.

There is a bridge rectifier made from four 1N4007 diodes.This was permanently connected to two CR2032 3V lithium cells and a black cylindrical component, 10mm dia, 5mm long. A solenoid coil of 4.8thou wire, 212Ω, 27mH, 23mm long, 21.5mm od was connected across the bridge. A magnet, 15.2mm dia, 17.5mm long was fitted into a tube and allowed to slide inside the coil with a buffer at each end.

A white LED in series with a 5Ω resistor could be switched to the bridge.

The two cells were showing 0V and 0.1V so these were removed and the torch shaken vigorously to no effect.
A 3V meter on ohms range would light the led.
I assume that the small cylindrical component is a super dooper capacitor but those I have looked up have a maximum voltage of 5V and here it would be continuously connected to 6V.

Can lithium cells be recharged?
Do you think that 1N4007 diodes are man enough for the job?:)
Is this a scam, it being just a small battery driven torch?
Should I remove the capacitor, replace the cells and forget shake rattle and roll?

It was interesting but probably pointless.
 

kellys_eye

Jun 25, 2010
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I'd say scam - much like the 'solar powered calculators' that are fitted with CR2032's (or similar) that last forever.....
 

Harald Kapp

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Nov 17, 2011
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These could have been rechargeable cells (not common, but available). If they were, they are probably useless by now due to deep discharge.


A test you can perform:
- remove the batteries, the LED and the black cylincrical component (leaving coil and rectifier only)
- connect a largish capacitor (some 100 µF) across the output of the rectifier without the LED attached.
- shake the torch and check the voltage on the capacitor. Does ist rise? If so, the generator works. If not, either the generator is defect or the rectifier.
- check the AC voltage on the input of the rectifier to isolate the generator.

super dooper capacitor but those I have looked up have a maximum voltage of 5V
There are 5.5V or 6V types, but chances are a standard 5 V type was used hoping the capacitor would survive 6 V for at least as long as the torch was under warranty.
 

73's de Edd

Aug 21, 2015
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Sir duke37


Your best chance on making one of those work is to use schottky diodes for the FWB, replace the existing magnet with a cluster of proper diameter stuck together silver colored niobdnium super magnets to add up to the duplicate length and just for testing use 2 series connected 10850 sized Lii ion cells .
if all is then up to your Jello "shake a pudding" expectations, smaller AA sized Li ions can be subbed in.
My situation, was making this technology work for an emergency radio, which, after those changes, played about 30 mins until needing a reshaking beat to the music.
In your case, you are just gong to have to sing or Hummmmmm loudly.
Making up for the original weaker magnet, the diodes loss and original leakier battery made the unit finally work satisfactorily.

73's de Edd
 
Last edited:

debe

Oct 15, 2011
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I found those torches are not very effective, they rely more on the batterys than shaking the torch ( I threw mine out)
 
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